encode.v.bak

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/*****************************************/
/**        8bit RISC MCU desing         **/
/**           encode module             **/
/**            BY yuzhijie              **/
/**            2006.10.22               **/
/*****************************************/
`timescale 1ns/100ps
module encode(clk2,reset,encode,alu_z,alu_bitz,choice,sel_imm,
              sel_wd,load_pc,load_pc_call,load_pc_goto,load_pc_retlw,
              w_reg,r_reg,w_ena,ir_jump);
    //encode:ir reg's output
    //alu_z :judge the opcode is 0 or 1
    //alu_z_b :bit operation is 0 or 1
    //choice :what's operation of alu
    //sel_wd :select direct or indirect
    //sel_imm :select tmp2 is ram_out or literal
    //load_pc :pc ena
    //load_pc_call :call
    //load_pc_goto :goto
    //load_pc_retlw :retlw
    //w_reg :write of ram
    //r_reg :read of ram
    //w_ena :w ena
    //sel_win :select input data of w reg
    //ir_jump :jump instruction
    input clk2,reset,alu_z,alu_bitz;//alu_z,alu_bitz;
    input [11:0]encode;
    output sel_imm,sel_wd,load_pc,load_pc_call,ir_jump;
    output load_pc_goto,load_pc_retlw,w_reg,r_reg,w_ena;
    output [4:0]choice;
    reg [4:0]choice;
    reg sel_imm,sel_wd,load_pc,load_pc_call,ir_jump;
    reg load_pc_goto,load_pc_retlw,w_reg,r_reg,w_ena;
always @(posedge clk2 or reset)
begin
    if(reset)
    begin
        sel_imm<=1'b0;
        sel_wd<=1'b0;
        load_pc<=1'b0;
        load_pc_call<=1'b0;
        load_pc_goto<=1'b0;
        load_pc_retlw<=1'b0;
        w_reg<=1'b0;
        r_reg<=1'b0;
        w_ena<=1'b0;
        ir_jump<=1'b0;
        choice<=5'bxxxxx;
    end
    else
    ctl_cycle;
end
task ctl_cycle;
    begin
        casex(encode)
            12'b0001_11??_????://ADDWF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b00000;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
                else if(encode[5]==1)
                begin
                    choice<=5'b00000;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
            end
            12'b1100_????_????://MOVLW
            begin
                w_ena<=1'b1;
                sel_imm<=1'b0;
                sel_wd<=1'b0;
                load_pc<=1'b0;
                load_pc_call<=1'b0;
                load_pc_goto<=1'b0;
                load_pc_retlw<=1'b0;
                w_reg<=1'b0;
                r_reg<=1'b0;
                ir_jump<=1'b0;
                choice<=5'b00001;
            end
            12'b0001_01??_????://ANDWF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b00010;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
                else if(encode[5]==1)
                begin
                    choice<=5'b00010;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
            end
            12'b0000_011?_????://CLRF
            begin
                choice<=5'b00011;
                sel_imm<=1'b0;
                w_ena<=1'b0;
                sel_wd<=1'b0;
                load_pc<=1'b0;
                load_pc_call<=1'b0;
                load_pc_goto<=1'b0;
                load_pc_retlw<=1'b0;
                w_reg<=1'b1;
                r_reg<=1'b0;
                ir_jump<=1'b0;
            end
            12'b0000_0100_0000://CLRW
            begin
                choice<=5'b00100;
                sel_imm<=1'b0;
                w_ena<=1'b1;
                sel_wd<=1'b0;
                load_pc<=1'b0;
                load_pc_call<=1'b0;
                load_pc_goto<=1'b0;
                load_pc_retlw<=1'b0;
                w_reg<=1'b0;
                r_reg<=1'b0;
                ir_jump<=1'b0;
            end
            12'b0001_00??_????://IORWF
            begin
                if(encode[5]==0)
                begin 
                    choice<=5'b00101;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
                else if(encode[5]==1)
                begin
                    choice<=5'b00101;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
            end
            12'b0010_00??_????://MOVF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b00110;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b1;
                    ir_jump<=1'b0;
                end
                else if(encode[5]==1)
                begin
                    choice<=5'b00110;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b1;
                    ir_jump<=1'b0;
                end
            end
            12'b0000_001?_????://MOVWF
            begin
                choice<=5'b00111;
                sel_imm<=1'b1;
                w_ena<=1'b1;
                sel_wd<=1'b0;
                load_pc<=1'b0;
                load_pc_call<=1'b0;
                load_pc_goto<=1'b0;
                load_pc_retlw<=1'b0;
                w_reg<=1'b1;
                r_reg<=1'b0;
                ir_jump<=1'b0;
            end
            12'b0000_0000_0000://nop
            begin
                choice<=5'b01000;
                sel_imm<=1'b0;
                w_ena<=1'b0;
                sel_wd<=1'b0;
                load_pc<=1'b0;
                load_pc_call<=1'b0;
                load_pc_goto<=1'b0;
                load_pc_retlw<=1'b0;
                w_reg<=1'b0;
                r_reg<=1'b0;
                ir_jump<=1'b0;
            end
            12'b0011_01??_????://RLF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b01001;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
                else if(encode[5]==1)
                begin
                    choice<=5'b01001;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
            end
            12'b0011_00??_????://RRF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b01010;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
                else if(encode==1)
                begin
                    choice<=5'b01010;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
            end
            12'b0000_10??_????://SUBWF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b01011;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                   ir_jump<=1'b0;
               end
               else if(encode[5]==1)
               begin
                    choice<=5'b01011;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                   ir_jump<=1'b0;
               end
            end
            12'b0011_10??_????://SWAPF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b01100;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
                else if(encode[5]==1)
                begin
                    choice<=5'b01100;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
            end
            12'b0001_10??_????://XORWF
            begin
                if(encode[5]==0)
                begin
                    choice<=5'b01101;
                    sel_imm<=1'b1;
                    w_ena<=1'b1;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b0;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
                else if(encode[5]==1)
                begin
                    choice<=5'b01101;
                    sel_imm<=1'b1;
                    w_ena<=1'b0;
                    sel_wd<=1'b0;
                    load_pc<=1'b0;
                    load_pc_call<=1'b0;
                    load_pc_goto<=1'b0;
                    load_pc_retlw<=1'b0;
                    w_reg<=1'b1;
                    r_reg<=1'b0;
                    ir_jump<=1'b0;
                end
            end
            12'b1110_????_????://ANDLW
            begin
                choice<=5'b01110;
                sel_imm<=1'b0;
                w_ena<=1'b1;
                sel_wd<=1'b0;
                load_pc<=1'b0;
                load_pc_call<=1'b0;
                load_pc_goto<=1'b0;
                load_pc_retlw<=1'b0;